1. Field
Various embodiments of the present disclosure relate to a nano structure, a fabrication method thereof, and an application device thereof.
2. Description of the Related Art
Nano structures have such characteristics as the quantum confinement effect, the Hall-Petch effect, dropping melting point, resonance phenomenon, excellent carrier mobility and so forth in comparison with conventional bulk and thin firm-type structures. For this reason, the nano structure is being applied to chemical batteries, solar cells, semiconductor devices, chemical sensors, photoelectric devices and the like.
Nano structures are generally fabricated in either a top-down method or a bottom-up method. The bottom-up method includes a vapor-liquid-solid growth method and a liquid growth method. The vapor-liquid-solid growth method is based on a catalytic reaction, and includes methods such as the Thermal Chemical Vapor Deposition (thermal-CVD) method, the Metal-Organic Chemical Vapor Deposition (MOCVD) method, the Pulsed Laser Deposition (PLD) method, and the Atomic Layer Deposition (ALD) method. As for the liquid growth method, a self-assembly technology and a hydrothermal method are being suggested.
According to the conventional bottom-up method, nanoparticles are prepared in advance and then the nanoparticles are attached to a substrate having a modified surface. However, this method is limited because of nanoparticle size issues that affect the reproducibility and reliability of memory devices in which it is implemented. In other words, with the method of fabricating a nano structure by simply attaching nanoparticles to a substrate, it is likely impossible to improve memory performance unless nanoparticle synthesis technology makes remarkable progress.
To overcome this limitation, nanoparticles may be prepared in a top-down method such as with lithography. The use of the top-down method, however, requires a great deal of investment in equipment, because a high-end lithography facility is needed. Moreover, since the process is quite complicated, the ability to implement it in mass-production is limited. Also, although the etch process is performed using an electron beam, it is difficult to keep the nanoparticle size under a predetermined level.